The wind in June-July can be OK, it is a SW monsoonal wind, so west facing coast of Phuket / Ko Samui is your best bet, and if your desperate, Pattaya (sin city). Wind averages around 12 knots so big kites.
Phuket can get some good surf this time of year. KiteboardingAsia.com have a great location in Phuket, you can also contact
[email protected]cheers